Derivative Instruments (Credit-Risk-Related Contingent Features) (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Derivative [Line Items]
Fair value of derivative instruments with credit-risk-related contingent features that were in a liability position	$ 2,100	$ 2,700
Total required posted collateral should FPL's and Capital Holdings' credit ratings fall to BBB/Baa2	250	700
Total required posted collateral should FLP's and Capital Holdings' credit ratings fall below investment grade	2,300	2,800
Additional collateral requirements if non-ratings based contract provisions are triggered	720	850
Collateral Already Posted	157
Letters of credit posted through the normal course of business that could be applied toward the collateral requirements related to derivative instruments with credit-risk-related contingent features	18	236
FPL [Member]
Derivative [Line Items]
Fair value of derivative instruments with credit-risk-related contingent features that were in a liability position	173	369
Total required posted collateral should FPL's and Capital Holdings' credit ratings fall to BBB/Baa2	30	130
Total required posted collateral should FLP's and Capital Holdings' credit ratings fall below investment grade	600	700
Additional collateral requirements if non-ratings based contract provisions are triggered	160	200
Collateral Already Posted	0
Letters of credit posted through the normal course of business that could be applied toward the collateral requirements related to derivative instruments with credit-risk-related contingent features	$ 0	$ 0